JP5185557B2 - Equipment for improving residual stress in pipes - Google Patents

Description

  The present invention relates to a tubular body residual stress improving apparatus for improving a residual stress of a tubular body such as a pipe.

  When installing a pipe body such as a large pipe in a nuclear power plant, a large plant, etc., removal of stress remaining in the pipe when welding is a problem. When welding is performed, residual stress is generated in the pipe, and the residual stress may shorten the life of the pipe. Therefore, it is desirable to remove the residual stress generated by welding.

  As a method of improving the residual stress remaining in the pipe, the inventors of the present application irradiate the outer peripheral surface of the pipe while moving the laser around, rapidly heat it to a temperature that does not adversely affect the material, and apply it to the inner and outer faces of the pipe. The method of reducing the residual stress of piping is proposed by forming a temperature difference (patent documents 1 to 4).

JP 2006-035292 A JP 2006-015399 A JP 2006-037199 A JP-A-2005-232586

  As in Patent Documents 1 to 4, etc., in the method of reducing the residual stress of the pipe by laser irradiation, when the diameter of the pipe to be irradiated is relatively small, the light that escapes to the circumference of the pipe in the circumferential direction of the pipe As a result, there are problems that the amount of light leakage increases and it becomes difficult to secure sufficient light intensity at the end of the irradiation region. Also, in the axial direction of the pipe, since there is irradiation outside the necessary area, an extra laser output is necessary to obtain the desired heat input characteristics within the desired area. In addition, when taper-shaped pipes with varying pipe diameters are targeted for irradiation, the heat input distribution changes abruptly at the boundary between the pipe taper part and straight part. It was difficult to obtain a desired heat input distribution for the straight portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an apparatus for improving a residual stress of a tubular body that controls an optical path of a laser beam and suppresses irradiation to an unnecessary region.

A tubular body residual stress improving apparatus according to a first aspect of the present invention for solving the above problems is as follows.
Rotational drive means for moving around the outer circumference of the cylindrical tube;
The held to a rotary drive means, as well as several irradiating a laser beam to the outer peripheral surface of the welded portion of the tubular body from the laser light source and a front Kifuku number of adjustable light control unit irradiation area by the laser beam Have
By moving the irradiation region by the laser light before Kifuku number in a circumferential direction of the tubular body, the tubular-body residual-stress improving apparatus for improving the residual stress of the tube,
The light control unit
The optical system of the laser light at at least one end has a lens for shifting the optical axis of the laser light in the optical system, and the lens causes the intensity peak of the laser light at the end to be outside the axial direction of the tubular body. The optical axis of the laser beam is shifted so as to be biased to irradiate the tube body,
The other laser light optical system has a trapezoidal prism with a trapezoidal side faced in the axial direction of the tube, and the trapezoidal prism allows the inner side of the skirt portion of the laser beam in the circumferential direction to be inside. The tube body is refracted and irradiated to the tube body.

A tubular body residual stress improving apparatus according to a second invention for solving the above-mentioned problems is as follows.
In the tubular body residual stress improving apparatus according to the first invention,
When the optical system of the laser light at one end has the lens, the light control unit replaces the lens that shifts the optical axis of the laser light with the optical system of the laser light at the other end. The other trapezoidal prism disposed in the circumferential direction of the tubular body, the other trapezoidal prism refracts the skirt portion of the end portion of the laser beam in the axial direction of the tubular body, The tube is irradiated.

A tubular body residual stress improving apparatus according to a third invention for solving the above-mentioned problems is
In the residual stress improving apparatus for a tubular body described in the first or second invention,
Wherein instead of trapezoidal prisms, characterized by using a multifaceted prism having a surface having a surface on the emission side is more than three.
A tubular body residual stress improving apparatus according to a fourth invention for solving the above-described problems is
In the tubular body residual stress improving apparatus described in the second invention,
Instead of the trapezoidal prism and the other trapezoidal prisms, a polyhedral prism having more than three surfaces on the exit side is used.

A tubular body residual stress improving apparatus according to a fifth invention for solving the above-mentioned problems is as follows.
In the tubular body residual stress improving apparatus according to the second invention,
Instead of the other trapezoidal prism, a hexahedral prism made of a truncated quadrangular pyramid is used, and the hexahedral prism refracts the skirt portion in the circumferential direction of the tubular body of the laser beam at the end, and The base portion of the laser beam in the axial direction of the tube body is refracted inward to irradiate the tube body.

A tubular body residual stress improving apparatus according to a sixth invention for solving the above-mentioned problems is as follows.
Rotational drive means for moving around the outer circumference of the cylindrical tube;
Light control that is held by the rotation driving means and that irradiates one or more laser beams from a laser light source to the outer peripheral surface of the welded portion of the tube, and that can adjust the irradiation area by the one or more laser beams And
In the apparatus for improving residual stress of a tubular body that improves the residual stress of the tubular body by moving the irradiation region of the one or more laser beams in the circumferential direction of the tubular body,
The light control unit has a lens that shifts the optical axis of the laser light in the optical system in the optical system of the laser light in at least one end, and the lens causes an intensity peak of the laser light in the end to be in the tube. The tube is irradiated with the optical axis of the laser beam shifted so as to be biased outward in the axial direction of the body.

A tubular body residual stress improving apparatus according to a seventh invention for solving the above-mentioned problems is
In the residual stress improving apparatus for a tubular body described in any one of the first to sixth inventions,
The optical system of the laser beam is arranged in one housing.

An apparatus for improving a residual stress of a tubular body according to an eighth invention for solving the above-mentioned problems is as follows.
In the tubular body residual stress improving apparatus described in any one of the first to seventh inventions,
An aspheric lens is used in the optical system of the light control unit.

According to the first to fifth inventions, since the light at the skirt portion of the laser beam is refracted inward using the prism, a sufficient irradiation intensity is ensured at the end of the irradiation region, and an unnecessary region. It is possible to reduce the waste of the output of the laser beam by suppressing the irradiation of the laser beam.

According to the first and sixth inventions, the optical axis of the laser beam is shifted so that the peak position of the laser beam on the irradiation surface is shifted outward in the axial direction using the axis shifting lens. At the end of the direction, sufficient irradiation intensity can be secured, and irradiation of laser light to unnecessary areas can be suppressed to reduce waste of laser light output.

According to the seventh invention, since a plurality of optical systems are arranged in one housing, the adjustment range of each optical system can be increased, and leakage light can be suppressed to damage the device or cause a disaster. Can be prevented.

According to the eighth invention, since the aspherical lens is used in the optical system, the number of lenses to be used can be reduced and the configuration of the light control unit can be made simple and small. In addition, a desired irradiation profile can be formed by forming the aspheric lens according to the shape of the irradiation target.

  The tubular body residual stress improving apparatus according to the present invention will be described in detail with reference to FIGS.

Reference example 1

FIG. 1 is a schematic diagram showing a tubular body residual stress improving apparatus according to the present invention.
As shown in FIG. 1, the residual stress improving apparatus 1 is arranged so as to be able to move around the outer periphery of a pipe 2 that is a cylindrical tube body, and can be controlled in rotational speed in the circumferential direction (rotation drive means). And an arm part 4 supported by the rotation drive device 3 and extending in the axial direction of the pipe 2, and capable of rotating around the pipe 2 coaxially with the pipe 2, and held by the arm part 4, and welding of the pipe 2 A light control unit 5 that irradiates a predetermined region on the outer peripheral surface of the part W with a plurality of laser beams 9 and a plurality of optical fibers 6 are connected to the light control unit 5, and the laser light is transmitted through the optical fibers 6 to the light control unit 5. And a control unit 8 for controlling the rotary drive device 3, the laser oscillator 7 and the like.

  The rotation drive device 3 can be attached to and detached from the outer periphery of the pipe 2 and can be freely installed around a place where the residual stress is desired to be improved, for example, a welded portion W or the like. The rotary drive device 3 may have any configuration as long as the inner peripheral side holds the pipe 2 and the outer peripheral side that supports the arm portion 4 can circulate. For example, the rotary drive device 3 holds the pipe 2 on the inner peripheral side. It may be configured to include a fixed portion and a surrounding portion that supports the arm portion 4 and circulates around the pipe 2 coaxially with the pipe 2 on the outer peripheral side.

  The light control unit 5, the optical fiber 6, and the laser oscillator 7 constitute a heating optical system, and a plurality of laser beams 9 are generated by the light control unit 5 disposed on the arm unit 4 along the axial direction of the pipe 2. The predetermined area on the outer peripheral surface of the pipe 2 is irradiated to uniformly heat the predetermined area. Although details will be described later, in the light control unit 5, the circumferential irradiation width and the axial irradiation width are adjusted by adjusting the positions of the lenses, mirrors, and the like constituting the light control unit 5 so that a desired heating region is obtained. Is adjusted. Here, as an example, the number of optical fibers 6 is plural, and the laser light 9 applied to the pipe 2 corresponding to each optical fiber 6 is also P1 to Pn. The number of laser beams 9 to be applied can be changed as appropriate according to the irradiation conditions, and any configuration that irradiates at least one laser beam 9 may be used.

  When the residual stress is improved, in the residual stress improving apparatus 1 according to the present invention, the heating region is adjusted in advance by the adjustment of the light control unit 5, and the output of the laser oscillator 7 is controlled and rotated by the control unit 8. By moving the driving device 3 around at a predetermined moving speed, the laser light 9 irradiated from the light control unit 5 irradiates a predetermined region on the outer peripheral surface of the pipe 2 while moving around the outer periphery of the pipe 2. Thus, a predetermined area on the outer peripheral surface of the pipe 2 is heated. At this time, the residual stress on the inner surface after cooling is reduced or improved to compressive stress by utilizing the temperature difference between the inner and outer surfaces of the pipe 2 generated during heating and causing the inner surface to yield. The number of laps may be one lap, but may be a plurality of laps. In the case of a plurality of laps, the start / end positions may be changed. The heating temperature is preferably less than the solution temperature. Furthermore, in the case of the present invention, it is not always necessary to forcibly cool the inner surface side of the pipe 2.

  First, the principle of improving the residual stress in the tubular residual stress improving apparatus according to the present invention will be briefly described.

  In the case of improving the residual stress in a predetermined region near the welded portion W of the pipe 2, in the present invention, the outer peripheral surface of the pipe 2 is heated with laser light, and a predetermined temperature difference is formed between the outer surface and the inner surface of the pipe 2. Heat so that. When such heating is performed, the outer surface is in a compressive stress state, the inner surface is in a tensile stress state, and further, the inner surface is in a tensile yield state. After heating, there is no temperature difference between the inner and outer surfaces of the specified area, and when the temperature drops to near room temperature, the outer surface becomes a tensile stress state, the inner surface becomes a compressive stress state, and the residual stress on the inner surface is reduced by the yield stress. It becomes possible to improve from a state to a compressive stress state. At this time, it is desirable to set the conditions during laser heating so that the magnitude (strain amount) of the stress generated during heating is at least the strain equivalent to or greater than the yield stress. In this way, the residual stress generated on the inner surface of the pipe 2 can be improved from a tensile state to a compressed state, and as a result, stress corrosion cracking on the inner surface of the pipe body can be prevented.

  As described above, in order to obtain the desired strain amount by laser heating the outer peripheral surface of the pipe 2 (near the welded portion W), it is necessary to control the axial irradiation width and the circumferential irradiation width within appropriate ranges. . The axial irradiation width and circumferential irradiation width depend on the shape of the pipe 2 (specifically, the diameter and thickness of the pipe 2), and the material of the pipe 2, the installation environment, and the like. Accordingly, appropriate axial direction irradiation width and circumferential direction irradiation width are set.

  However, since the laser beam supplied to the light control unit 5 is supplied using the optical fiber 6 or the like, the original irradiation area is not wide, and in order to obtain the desired axial irradiation width and circumferential irradiation width. It was necessary to expand the irradiation area using a lens, a concave mirror, and the like. In that case, it is difficult to secure a sufficient light intensity at the end of the irradiation region, and that portion cannot be regarded as an irradiation region for heat input, resulting in a useless irradiation region. Accordingly, in order to obtain a desired heat input at the ends of the axial irradiation width and the circumferential irradiation width, a larger laser output is required. In addition, when the diameter of the pipe 2 to be irradiated is relatively small, the light at the circumferential end of the irradiation area escapes to the outside of the pipe 2, and the amount of light leakage increases and the light is substantially irradiated. It was difficult to ensure sufficient light intensity at the circumferential end of the irradiated portion of the pipe 2.

  Thus, in the tubular body residual stress improving apparatus according to the present invention, the configuration of the optical system in the light control unit 5 is devised in order to overcome the above-described problems. In the following description, unless otherwise specified, the circumferential direction means the circumferential direction of the pipe 2, and the axial direction means the axial direction of the pipe 2.

FIG. 2A shows a schematic configuration diagram as an example of an embodiment of the light control unit 5, and the configuration will be described. In FIG. 2 (a), for the sake of clarity, an optical system of only the laser beams P1 and Pn out of a plurality of laser beams is illustrated, and actually, the optical system is enlarged or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the characteristic optical paths in this reference example are shown.

The light control unit 5A of this reference example controls the laser beams P1 to Pn. The optical system on each optical path has an equivalent configuration. For example, in the laser light P1, as shown in FIG. 2A, the protective glass 11, The lens 12, the mirror 13, and the lens 14 are included. Accordingly, in the laser light P1, the laser light emitted from the optical fiber 6 is incident on the protective glass 11 that protects the optical system, and the laser light that has passed through the protective glass 11 is magnified by the lens 12, and then the lens 12 The laser beam magnified by is reflected in the direction of the pipe 2 by the mirror 13, and the laser beam reflected by the mirror 13 is further magnified by the lens 14 and irradiated to a desired region of the pipe 2.

However, since the light intensity at the end portion in the circumferential direction of the irradiation region remains insufficient with only the optical system, in this reference example, it is the final stage of the optical system of the laser beams P1 to Pn, and A pair of mirrors 21 and 22 are arranged on both sides in the circumferential direction of the optical paths of the optical systems of the laser beams irradiated onto the pipe 2. These mirrors 21 and 22 are arranged so as to reflect the laser light at the skirt portion in the circumferential direction of the enlarged laser light and to fold the laser light back to a desired irradiation region of the pipe 2.

  With such a configuration, at the circumferential end of the irradiation region of the pipe 2, the laser beam that has been transmitted through the lens 14 and directly applied to the pipe 2 and the lens 14 are transmitted and reflected by the mirrors 21 and 22. The laser beam is irradiated so as to overlap. As a result, the escape light can be suppressed and the output can be used effectively, and the light intensity at the circumferential end of the irradiation region of the pipe 2 can be controlled to make the rise steep. Here, in consideration of ease of adjustment, a pair of mirrors 21 and 22 that can be shared by all the optical systems of the laser beams P1 to Pn are provided. Instead, a mirror may be provided independently for each of the laser beams P1 to Pn.

  Therefore, conventionally, the irradiation area of the pipe 2 is obtained by effectively using the mirrors 21 and 22 to illuminate the outside of the pipe 2 and the bottom part of the laser beam that has hardly contributed to the heat input to the necessary area. The light intensity at the end in the circumferential direction can be ensured. For example, as shown in a region A in FIG. 2B, the profile can be controlled so that the both ends in the circumferential direction rise sharply.

Reference example 2

FIG. 3A shows a schematic configuration diagram as another example of the embodiment of the light control unit 5, and the configuration will be described. In FIG. 3 (a), for the sake of clarity, the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is illustrated, and actually, it is enlarged or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the characteristic optical paths in this reference example are shown.

The light control unit 5B shown in FIG. 3A has the same configuration as the light control unit 5A shown in FIG. 2A of Reference Example 1 except for the mirror configuration. Therefore, the description of the configuration equivalent to that of the light control unit 5A of Reference Example 1 will be omitted, and the configuration of the light control unit 5B will be described.

In this reference example, in order to ensure the light intensity at the axial end of the irradiation region, both ends of the laser beams P1 to Pn irradiated to the pipe 2, that is, at the final stage of the optical system of the laser beams P1 and Pn. In addition, a pair of mirrors 23 and 24 are disposed on both ends in the axial direction of the optical paths of the optical systems of the laser beams P1 and Pn. The mirror 23 is disposed so as to reflect the laser beam at the skirt portion in the axial direction of the expanded laser beam P1 and to fold the laser beam to a desired irradiation region of the pipe 2, and the mirror 24 is configured to expand the laser beam. The laser beam is arranged so as to reflect the laser beam at the base portion in the axial direction of the light Pn and to fold the laser beam to a desired irradiation region of the pipe 2. In addition, when the laser beam irradiated to the pipe 2 is one system, for example, when the laser beam P1 is irradiated using only the laser beam P1, it is the final stage of the optical system of the laser beam P1, and A pair of mirrors 23 and 24 may be disposed on both ends of the optical path in the axial direction with respect to the final optical path of the optical system of the laser beam P1.

  With such a configuration, at the axial end of the irradiation region of the pipe 2, the laser beam that has passed through the lens 14 and is directly irradiated onto the pipe 2 and the lens 14, and are reflected by the mirrors 23 and 24. The laser beam is irradiated so as to overlap. As a result, irradiation outside the necessary area can be suppressed and the output can be used effectively, and the light intensity at the axial end of the irradiation area of the pipe 2 can be controlled to make its rise steep. .

  Therefore, conventionally, the base part of the laser beam that has hardly contributed to the heat input to the necessary region is effectively used by the mirrors 23 and 24 to secure the light intensity at the axial end of the irradiation region of the pipe 2. can do. For example, in FIG. 3B, the profiles P1 and Pn are Gaussian distribution profiles without the mirrors 23 and 24, but by arranging the mirrors 23 and 24, the region of FIG. As shown in FIG. 3B, it is possible to control the profile so that both ends in the axial direction rise steeply, and the temperature distribution given to the pipe 2 can also be controlled to a temperature profile as shown in FIG. In FIG. 3B, profiles other than P1 and Pn, for example, profiles such as P2 are omitted.

Reference example 3

FIG. 4 shows a schematic configuration diagram as another example of the embodiment of the light control unit 5, and the configuration will be described. In FIG. 4, for the sake of clarity, the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is illustrated, and actually, it is enlarged or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the characteristic optical paths in this reference example are shown.

Light control unit 5C shown in FIG. 4, except the structure of the mirror, the light control unit 5A shown in FIG. 2 of Reference Example 1 (a), a light control unit 5B shown in FIG. 3 of Reference Example 2 (a) It has an equivalent configuration. More specifically, in the light control unit 5C shown in FIG. 4, the mirrors 21 and 22 in the light control unit 5A and the mirrors 23 and 24 in the light control unit 5B are combined to form an optical system of the laser beams P1 to Pn. This is a boxed configuration surrounded by mirrors 21-24. Therefore, for the same structure as the optical control unit 5B of the light control unit 5A and Reference Example 2 Reference Example 1, omitting the overlapping description, the configuration of the optical control unit 5C.

In this reference example, in order to ensure the light intensity at the circumferential end and the axial end of the irradiation region, it is the final stage of the optical system, and on both sides in the circumferential direction with respect to the final optical path of the laser beam. The mirrors 21 and 22 are disposed, and the mirrors 23 and 24 are disposed on both sides in the axial direction. The mirrors 21 and 22 are arranged so as to reflect the laser light at the skirt portion in the circumferential direction of the expanded laser beams P1 to Pn and to fold the laser beam to a desired irradiation region of the pipe 2, and the mirrors 23 and 24 are The expanded laser beams P <b> 1 and Pn are arranged so as to reflect the laser beam at the base portion in the axial direction and to fold the laser beam to a desired irradiation region of the pipe 2.

  With such a configuration, at the end in the circumferential direction of the irradiation region of the pipe 2, the laser beam that has passed through the lens 14 and is directly irradiated onto the pipe 2 and the lens 14, and are reflected by the mirrors 21 and 22. The laser beam is irradiated so as to overlap. Further, at the axial end of the irradiation region of the pipe 2, a laser beam that has passed through the lens 14 and is directly irradiated onto the pipe 2, and a laser beam that has passed through the lens 14 and is reflected by the mirrors 23 and 24. Will be irradiated so as to overlap. As a result, it is possible to suppress the escape light and the irradiation outside the necessary area, and to effectively use the output, and to control the light intensity at the circumferential end and the axial end of the irradiation area of the pipe 2, The rise can be made steep.

  Accordingly, conventionally, the mirror 2, 22 effectively utilizes the circumferential skirt portion of the laser beam that has escaped to the outside of the pipe 2 and hardly contributed to the heat input to the necessary area, so that the pipe 2 In addition, it is possible to secure the light intensity at the circumferential end of the irradiation region of the laser beam, and in addition, the mirrors 23 and 24 effectively use the mirrors 23 and 24 to prevent the axial base of the laser beam that has hardly contributed to the heat input to the necessary region. By utilizing this, it is possible to ensure the light intensity at the axial end of the irradiation region of the pipe 2. Further, since the optical system of the laser beams P1 to Pn is surrounded by the mirrors 21 to 24 and boxed, leakage light to the periphery can be suppressed, and countermeasures against leakage light (protective plate or the like) are not required.

Reference example 4

  FIG. 5 shows a schematic configuration diagram as an example of the embodiment of the light control unit 5, and the configuration will be described. In FIG. 5, for the sake of clarity, the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is illustrated, and is actually magnified or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the main optical paths are shown.

As shown in FIG. 5, the light control unit 5D of this reference example also controls the laser beams P1 to Pn. The optical system on each optical path has the same configuration. For example, in the laser light Pn, the protective glass 31, the trapezoidal prism 32, the lens 33, the mirror 35, A protective glass 36 is provided. In other words, any one of the optical systems has, for example, a trapezoidal prism 32 on the front side of the optical system.

In this reference example, unlike the reference examples 1 to 3, a trapezoidal prism 32 having a trapezoidal side face arranged in the axial direction (in parallel to the circumferential direction) is used instead of the mirror to The optical path of the laser beam is refracted inward to ensure the light intensity at the circumferential end of the irradiation region.

  Therefore, for example, in the laser light Pn, the laser light emitted from the optical fiber 6 is incident on the protective glass 31 that protects the optical system, and the laser light that has passed through the protective glass 11 is the laser light at the base in the circumferential direction. The laser beam is refracted by the trapezoidal prism 32 that adjusts the optical path of the laser beam, and the laser beam refracted by the trapezoidal prism 32 is magnified by the lens 33, and then the laser beam magnified by the lens 33 is reflected by the mirror 35 toward the pipe 2. The laser beam reflected by the mirror 35 passes through the protective glass 36 and is irradiated to a desired region of the pipe 2. As the lens 33, a spherical lens is used. However, for example, a cylindrical lens or the like may be used, and one cylindrical lens is used for circumferential adjustment, and the other one lens is used for axial adjustment. May be.

  With such a configuration, the skirt portion of the laser beam that has hardly contributed to the escape light and heat input to the necessary region is refracted to the circumferential end of the irradiation region of the pipe 2 and irradiated. It will be. As a result, the escape light can be suppressed and the output can be used effectively, and the light intensity at the circumferential end of the irradiation region of the pipe 2 can be controlled to make the rise steep. Here, in consideration of ease of adjustment, the common mirror 35 and the protective glass 36 are provided for all the optical systems of the laser beams P1 to Pn. However, the common mirror 35 and the protective glass 36 are used instead. In addition, each of the laser beams P1 to Pn may be provided with a mirror and a protective glass independently.

  Therefore, conventionally, the trapezoidal prism 32 effectively uses the light that has escaped to the outside of the pipe 2 and the skirt part of the laser light that hardly contributes to the heat input to the necessary area. The light intensity at the circumferential end of the irradiation region can be ensured. If the trapezoidal prism 32 is adjusted for each of the laser beams P1 to Pn, it is possible to suppress a decrease in energy density at the beam base of the laser beam even when a small diameter tube is targeted.

  FIG. 6A shows a schematic configuration diagram as another example of the embodiment of the light control unit 5, and the configuration will be described. In FIG. 6 (a), the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is shown for the sake of clarity, and is actually magnified or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the main optical paths are shown.

The light control unit 5E shown in FIG. 6A has the same configuration as the light control unit 5D shown in FIG. 5 of Reference Example 4 except for the configuration of the optical system of the laser beam P1. Therefore, the description of the configuration equivalent to that of the light control unit 5D of Reference Example 4 will be omitted, and the configuration of the light control unit 5E will be described.

  In the present embodiment, a trapezoidal prism 37 is provided in place of the trapezoidal prism 32 in the optical system of the laser beam P1 on one end side. In other words, any one of the optical systems has a trapezoidal prism 37 on the front side of the optical system, for example. Unlike the trapezoidal prism 32, the trapezoidal prism 37 has a trapezoidal side surface arranged in the circumferential direction (parallel to the axial direction), and refracts the optical path of the laser beam at the base in the axial direction. The light intensity at the axial end of the irradiation region is ensured. A similar trapezoidal prism 37 may be provided in the optical system of the laser beam Pn on the other end side.

  Therefore, for example, in the laser light P1, the laser light emitted from the optical fiber 6 is incident on the protective glass 31 that protects the optical system, and the laser light that has passed through the protective glass 11 is the laser light at the base in the axial direction. The laser beam is refracted by the trapezoidal prism 37 that adjusts the optical path of the laser beam, and the laser beam refracted by the trapezoidal prism 37 is magnified by the lens 33, and then the laser beam magnified by the lens 33 is reflected by the mirror 35 toward the pipe 2. The laser beam reflected by the mirror 35 passes through the protective glass 36 and is irradiated to a desired region of the pipe 2.

  With such a configuration, a portion that has conventionally been a skirt portion of the laser beam that hardly contributes to heat input to the necessary region is refracted and irradiated to the end portion in the axial direction of the irradiation region of the pipe 2. . As a result, irradiation outside the necessary area can be suppressed and the output can be used effectively, and the light intensity at the circumferential end of the irradiation area of the pipe 2 can be controlled to make its rise steep. .

  Therefore, conventionally, the base portion of the laser beam that has hardly contributed to the heat input to the necessary region is effectively used by the trapezoidal prism 37 to secure the light intensity at the axial end of the irradiation region of the pipe 2. be able to. For example, in FIG. 6B, conventionally, if the trapezoidal prism 37 is not provided, the profile P1 is also a normal Gaussian distribution profile such as the profile Pn. Can be controlled to a trapezoidal profile with a flat top, and the temperature distribution given to the pipe 2 can also be controlled to a temperature profile as shown in FIG. Also in FIG. 6B, profiles other than P1 and Pn, for example, profiles such as P2 are omitted.

  7A and 7B are schematic configuration diagrams illustrating another example of the embodiment of the light control unit 5, and the configuration will be described. 7A is a top view thereof, and FIG. 7B is a perspective view thereof. 7A and 7B, for the sake of clarity, the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is shown, and actually, the optical system is enlarged by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn that are reflected or reflected, only the main optical path is shown.

As shown in FIGS. 7A and 7B, the light control unit 5F of this embodiment controls the laser beams P1 to Pn. In the present embodiment, the optical system other than the laser beams P1 and Pn has the same configuration as the optical system of the laser beams P1 and Pn in the reference example 4, and the laser beam travels in the traveling direction. A protective glass 31, a trapezoidal prism 32, a lens 33, a mirror 35, and a protective glass 36 are sequentially provided.

However, in this embodiment, the configuration is different from the optical systems of the laser beams P1 and Pn in Reference Example 4 and Example 1 . Specifically, the optical system of the laser beams P1 and Pn includes a protective glass 31, a lens 41, an optical axis shifting lens 43, a mirror 35, and a protective glass 36 in this order in the laser beam traveling direction. Yes. In other words, the optical axis shifting lens 43 is arranged so that the optical axes of the laser beams P1 and Pn are shifted and incident. Here, in the optical system of the laser beams P1 and Pn, the optical axis shift lens 43 shifts the optical axis so that the peak intensity of the laser beam on the irradiation surface is shifted outward in the axial direction, thereby reducing the base in the axial direction. The optical path of the laser beam of the part is shifted inward to ensure the light intensity at the end of the irradiation area in the axial direction.

  Accordingly, in the laser beams P1 and Pn, the laser beam emitted from the optical fiber 6 is incident on the protective glass 31 that protects the optical system, and the laser beam that has passed through the protective glass 31 is expanded by the lens 41, and then The laser beam magnified by the lens 41 is shifted inward in the axial direction by the optical axis shifting lens 43, and the laser light whose optical axis is shifted by the optical axis shifting lens 43 is reflected in the direction of the pipe 2 by the mirror 35. Then, the laser beam reflected by the mirror 35 passes through the protective glass 36 and is irradiated to a desired region of the pipe 2.

  With such a configuration, conventionally, a portion that has been a skirt portion of the laser beam that hardly contributes to heat input to the necessary region is irradiated while being shifted inward in the axial direction of the irradiation region on the surface of the pipe 2. Become. As a result, irradiation outside the necessary area can be suppressed and the output can be used effectively, and the light intensity at the axial end of the irradiation area of the pipe 2 can be controlled to make its rise steep. .

  Therefore, conventionally, the base portion of the laser beam that has hardly contributed to the heat input to the necessary region is effectively used by the optical axis shifting lens 43, so that the light intensity at the axial end of the irradiation region of the pipe 2 can be reduced. Can be secured. For example, in FIG. 8, when there is no optical axis shifting lens 43, the profiles P1 and Pn are also Gaussian distribution profiles, but the optical axis shifting lens 43 is used to shift the peak position in the axial direction to the end side. Thus, it is possible to make the profile asymmetric such that the profile on the end side rises sharply. In FIG. 8, profiles other than P1 and Pn, for example, profiles such as P2 are omitted.

In Reference Example 4 and Examples 1 and 2 described above, the trapezoidal prisms 32 and 37 are prisms having trapezoidal side surfaces, and have three surfaces on the exit side with respect to the bottom surface on the incident side. As a modification of Reference Example 4 and Examples 1 and 2 , instead of trapezoidal prisms 32 and 37, as shown in FIG. 9, a polyhedral prism 48 having more than three surfaces on the exit side is used. May be. In FIG. 9, the polygonal prism has five surfaces with respect to the bottom surface, but a polygonal prism having more surfaces formed according to a desired heat input profile may be used. By using such a polygonal prism, it is possible to adjust to a smoother heat input profile.

Further, in Reference Example 4, Examples 1 and 2 described above, the trapezoidal prism 32 and 37, but one side of the circumferential direction or the axial direction was prism as a trapezoid, Reference Example 4, Example 1 As a second modification, instead of the trapezoidal prisms 32 and 37, a hexahedral prism 49 made of a truncated quadrangular pyramid as shown in FIG. 10 may be used. This is a prism having a trapezoidal cross section in both the circumferential direction and the axial direction. By using such a hexahedral prism, the heat input profiles in the circumferential direction and the axial direction can be adjusted simultaneously.

Conventionally, the laser beams P1 to Pn have independent configurations and are arranged in independent casings. As a modification of the above-described Reference Example 4 and Examples 1 and 2 , the laser beam P1 is used. -Pn may be arranged in one housing. By arranging the laser beams P1 to Pn in one casing, a large amount of pitch adjustment of each optical system in the laser beams P1 to Pn can be secured.

Reference Example 5

  FIG. 11 shows a schematic configuration diagram as another example of the embodiment of the light control unit 5, and the configuration will be described. In FIG. 11, for the sake of clarity, the optical system of only the laser beams P1 and Pn out of the laser beams P1 to Pn is illustrated, and is actually enlarged or reflected by a lens, a mirror, or the like. Of the optical paths of the laser beams P1 and Pn, only the main optical paths are shown.

As shown in FIG. 11, the light control unit 5G of this reference example also controls the laser beams P1 to Pn. For example, the optical system of the laser beam P1 includes a light pipe 51, a lens 52, a mirror 54, and a lens 55 in that order in the traveling direction of the laser beam. That is, the light pipe 51 is provided on the front side of the optical system. As the lens 52, a spherical lens is used.

In this reference example, instead of the mirrors in the reference examples 1 to 3 and the trapezoidal prisms in the reference example 4 and the examples 1 and 2 , a rectangular cross section in which the energy density of the emitted light is made uniform and the irradiation shape is adjusted. A light pipe 51 having a shape or a square cross section is used. As can be seen from FIG. 12A, by using the light pipe 51, the profiles of the laser beams P1 and Pn become a trapezoidal profile with a steep rise and a flat top. As described above, by using the light pipe 51 whose profile shape is adjusted, the light intensity at the end of the irradiation region is prevented from being insufficient. Also in FIG. 12A, profiles other than P1 and Pn, for example, profiles such as P2 are omitted.

  Therefore, in the laser beams P1 to Pn, the laser beam emitted from the optical fiber 6 is incident on the light pipe 51 in which the energy density of the emitted light is made uniform and the irradiation shape is adjusted. The laser beam that has been made uniform and whose irradiation shape has been adjusted is magnified by the spherical lens 52, and then the laser beam magnified by the spherical lens 52 is reflected in the direction of the pipe 2 by the mirror 54 and is reflected by the mirror 54. The light is magnified by the spherical lens 55, imaged and projected onto a desired area of the pipe 2, and irradiated. By using the light pipe 51, the projection magnification of the optical system via the lens 52 or the like can be set small with respect to the image of the end face of the fiber 6, and as a result, aberration suppression is facilitated. In addition, the lens 52 can be a small-diameter lens, and an optical system can be configured with a combination of lenses with good manufacturability.

  With such a configuration, the profile of the irradiation region is adjusted so that the outside of the necessary region is not irradiated, and as a result, the light intensity at the axial end and the circumferential end of the irradiation region of the pipe 2 is controlled. Thus, the rise can be made steep.

  Accordingly, as shown in FIG. 12 (a), in the laser beams P1 to Pn, it is possible to adjust the profile of the irradiation region to obtain a trapezoidal profile in which the profile on the end side rises sharply. The temperature distribution given to the pipe 2 can also be controlled to a temperature profile as shown in FIG.

  Also, in the circumferential direction, the light pipe 51 adjusts the profile of the irradiation area so that the profile on the end side rises steeply so that the light at the end in the circumferential direction of the irradiation area of the pipe 2 is obtained. Strength can be secured. Then, by adjusting the light pipes 51 of the laser beams P1 to Pn, for example, as shown in FIG. 12B, the circumferential width of heat input can be controlled stepwise in the axial direction. Such a change in the heat input width is effective when the circumferential irradiation width is changed at a different material boundary or the like.

Reference Example 6

In the reference example 5 , the light pipe 51 has a rectangular cross-sectional shape or a square cross-sectional shape. However, as a modification of the reference example 5 , the light pipe 51 is replaced with the light pipe 51 having a rectangular cross-sectional shape or a square cross-sectional shape. For example, a light pipe having a trapezoidal cross-sectional shape may be used. For example, when the pipe 2 to be irradiated has a taper portion, it is desirable that the irradiation region shape to the portion is a trapezoidal shape. Therefore, by using a light pipe having a trapezoidal cross-sectional shape, the trapezoidal irradiation shape is changed. Projection irradiation can be easily performed on the tapered portion of the pipe 2. In this way, by making the cross-sectional shape of the light pipe in accordance with the irradiation region, it is possible to easily perform irradiation that matches the irradiation target. If there is a margin in laser output, a light pipe having a circular cross section or an elliptic cross section may be used.

Reference Example 7

The reference example 5 performs heat input by projecting the cross-sectional shape onto the irradiation target pipe 2 using the light pipe 51. In order to obtain a desired heat input profile and irradiation area, it is necessary to control not only the projected shape but also the uniformity of the projected image. However, the spread of the laser light reaching the light pipe 51 from the laser oscillator 7 through the optical fiber 6 has some individual differences, and is not necessarily uniform for all the laser lights P1 to Pn. Therefore, as shown in FIG. 13, by setting the light pipes 51a and 51b to a length corresponding to each light source (for each laser light P1 to Pn), the profile of the laser light incident on the light pipe 51 changes. Also, the difference can be absorbed (see FIG. 14B described later). Thus, by making the length of the light pipe 51 different for each light source, it is possible to uniformly irradiate with a desired irradiation shape.

  Further, the light pipes 51a and 51b may be used so as to be long enough to absorb the characteristic difference between the light sources so as to absorb such a characteristic difference between the light sources. Further, the position of the end face of the optical fiber may be changed. A variable length light pipe may be used in case the characteristics on the light source side change. In addition, as the variable length light pipe, for example, a plurality of copper-coated casings that are mirror-coated are used, and a light pipe that is variable in length can be configured by sliding them. realizable. In this way, by making the light pipe longer, the reflection is repeated many times in the light pipe, and the energy density is made uniform, so that the difference in the spread characteristics of the laser light can be canceled.

  For example, FIG. 14A shows the profile of the laser beam when the used light pipe is short. In this case, depending on the light source, the skirt portion of the irradiation region does not have a beautifully raised shape, or the top portion. The profile is greatly recessed or a desired profile is not necessarily obtained. On the other hand, when the length of the light pipe is increased according to the light source (for example, about twice as long), a substantially trapezoidal profile is obtained as shown in FIG. As described above, even if the profile of the laser light incident on the light pipe changes, the change can be absorbed by making the light pipe longer to some extent to obtain a desired profile.

In Reference Examples 1 to 7 and Examples 1 to 5 described above, the lenses 12, 33, and 52 are spherical lenses. However, as a modification of Reference Examples 1 to 7 and Examples 1 to 5, lenses are used. Instead of 12, 33, 52, an aspherical lens or a cylindrical lens may be used. If an aspheric lens is used, the number of lenses to be used can be suppressed, and the light control unit 5 can be configured to be usable even in a narrow area. If a cylindrical lens is used, the circumferential direction and axis of the pipe 2 can be reduced. Control of the laser beam in the direction can be performed independently. When the number of lenses is suppressed by the aspherical lens, the loss of laser light in the optical system can be suppressed, so that the tolerance of the apparatus output can be improved and the apparatus cost can be reduced. In the case of Reference Examples 1 to 5 and Examples 1 to 5 , for example, when heat is input to a different-diameter pipe, the rapid change in heat input caused by the shape difference at the boundary between the tapered portion and the straight portion is suppressed. Further, by forming an aspheric lens, a smooth profile corresponding to the shape can be obtained. In Reference Examples 6 and 7 , by using an aspheric lens, a desired projection irradiation shape can be obtained and aberration correction can be easily performed. Even when the dimensions of the irradiation region are changed, it is possible to form a profile in which the end of the irradiation region rises sharply. In addition, the irradiation intensity ratio can be adjusted to a desired ratio at the center portion / bottom portion of the irradiation region.

  The present invention is suitable for improving the residual stress of a cylindrical pipe.

It is a schematic block diagram which shows an example of embodiment of the residual stress improvement apparatus of the tubular body which concerns on this invention. (A) is a schematic block diagram which shows an example ( reference example 1) of embodiment of the light control part in the residual stress improvement apparatus of the tubular body which concerns on this invention, (b) demonstrates the effect. It is a graph. (A) is a schematic block diagram which shows another example ( reference example 2) of embodiment of the light control part in the residual-stress improvement apparatus of the tubular body which concerns on this invention, (b) is the effect. It is a graph to explain. In the residual stress improvement apparatus of the tubular body concerning the present invention, it is a schematic structure figure showing other examples ( reference example 3) of an embodiment of the light control part. In the residual stress improvement apparatus of the tubular body concerning the present invention, it is a schematic structure figure showing other examples ( reference example 4) of an embodiment of the light control part. (A) is a schematic block diagram which shows another example (Example 1 ) of the embodiment of the light control part in the residual-stress improvement apparatus of the tubular body which concerns on this invention, (b) is the effect. It is a graph to explain. In the residual stress improvement apparatus of the tubular body which concerns on this invention, it is a schematic block diagram which shows another example (Example 2 ) of embodiment of the light control part, (a) is the upper view, (b ) Is a perspective view thereof. It is a graph explaining the effect of the light control part shown in FIG. FIG. 5 is a perspective view showing an example of a multi-faceted prism used for the light control unit in the tubular residual stress improving apparatus according to the present invention. FIG. 3 is a perspective view showing an example of a hexahedral prism used for the light control unit in the tubular body residual stress improving apparatus according to the present invention. In the residual stress improvement apparatus of the tubular body which concerns on this invention, it is a schematic block diagram which shows another example ( reference example 5 ) of embodiment of the light control part. (A), (b) is a graph explaining the effect of the light control part shown in FIG. It is a schematic block diagram which shows the modification of the residual stress improvement apparatus of the tubular body which concerns on this invention shown in FIG. (A), (b) is a graph explaining the effect of the light control part shown in FIG.

DESCRIPTION OF SYMBOLS 1 Residual stress improvement apparatus 2 Piping 3 Rotation drive apparatus 4 Arm part 5 Optical control part 6 Optical fiber 7 Laser oscillator 8 Control part 9 Laser light 21, 22, 23, 24 Mirror 32, 37 Trapezoid prism 43 Axis offset lens 48 Polyhedral prism 49 Hexahedral prism 51 Light pipe

Claims (8)

Rotational drive means for moving around the outer circumference of the cylindrical tube;
A light control unit that is held by the rotation driving unit and irradiates a plurality of laser beams from a laser light source on the outer peripheral surface of the welded portion of the tubular body, and can adjust an irradiation region by the plurality of laser beams,
In the tubular body residual stress improving apparatus for improving the residual stress of the tubular body by moving the irradiation region by the plurality of laser beams in the circumferential direction of the tubular body,
The light control unit
The optical system of the laser light at at least one end has a lens for shifting the optical axis of the laser light in the optical system, and the lens causes the intensity peak of the laser light at the end to be outside the axial direction of the tubular body. The optical axis of the laser beam is shifted so as to be biased to irradiate the tube body,
The other laser light optical system has a trapezoidal prism with a trapezoidal side faced in the axial direction of the tube, and the trapezoidal prism allows the inner side of the skirt portion of the laser beam in the circumferential direction to be inside. An apparatus for improving a residual stress of a tubular body, wherein the tubular body is refracted and irradiated to the tubular body. The apparatus for improving residual stress in a tubular body according to claim 1,
When the optical system of the laser light at one end has the lens, the light control unit replaces the lens that shifts the optical axis of the laser light with the optical system of the laser light at the other end. The other trapezoidal prism disposed in the circumferential direction of the tubular body, the other trapezoidal prism refracts the skirt portion of the end portion of the laser beam in the axial direction of the tubular body, An apparatus for improving residual stress of a tubular body, wherein the tubular body is irradiated. In the apparatus for improving residual stress of a tubular body according to claim 1 or 2,
The trapezoid prism instead of arm, residual stress improving apparatus of the tubular body, which comprises using a multifaceted prism having a surface having a surface on the emission side is more than three. In the apparatus for improving residual stress in a tubular body according to claim 2,
An apparatus for improving residual stress in a tubular body, wherein a polyhedral prism having a number of surfaces on the exit side larger than three is used instead of the trapezoidal prism and the other trapezoidal prisms. In the tubular-body residual-stress improving apparatus of Claim 2,
Instead of the other trapezoidal prism, a hexahedral prism made of a truncated quadrangular pyramid is used, and the hexahedral prism refracts the skirt portion in the circumferential direction of the tubular body of the laser beam at the end, and An apparatus for residual stress improvement of a tubular body, wherein the bottom portion of the laser beam in the axial direction of the tubular body is refracted inward to irradiate the tubular body. Rotational drive means for moving around the outer circumference of the cylindrical tube;
Light control that is held by the rotation driving means and that irradiates one or more laser beams from a laser light source to the outer peripheral surface of the welded portion of the tube, and that can adjust the irradiation area by the one or more laser beams And
In the apparatus for improving residual stress of a tubular body that improves the residual stress of the tubular body by moving the irradiation region of the one or more laser beams in the circumferential direction of the tubular body,
The light control unit has a lens that shifts the optical axis of the laser light in the optical system in the optical system of the laser light in at least one end, and the lens causes an intensity peak of the laser light in the end to be in the tube. An apparatus for improving residual stress of a tubular body, wherein the tubular body is irradiated with the optical axis of the laser beam shifted so as to be biased outward in the axial direction of the body. In the residual stress improving apparatus tube body according to any one of claims of claims 1 to 6,
An apparatus for improving residual stress in a tubular body, wherein the optical system of the laser beam is arranged in one casing. In the apparatus for improving residual stress of a tubular body according to any one of claims 1 to 7 ,
An apparatus for improving residual stress in a tubular body, wherein an aspherical lens is used in the optical system of the light control unit.

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